Two of the robberies happened Saturday night on Vernon Street. Another attempted robbery happened 24 hours later on Summit Street near Mather Hall.

All three incidents took place on school grounds.

Among other changes, Hartford police, campus safety and the school’s private security firm are increasing patrols on and around campus in an effort to keep students safe.

The college is also upgrading security cameras and adding more blue-light alert phones. School officials emailed students reminding them to be alert while walking on campus, especially at night, and to keep their cellphones safely tucked away.

“I definitely think you should try to have things not visible,” said college sophomore Kathryn Orticerio.

School officials declined to comment on the security upgrades.

Hartford police said incidents like these happen all over the country, especially when new products are released, such as the iPhone 5S and 5C.

Police said they’ve arrested a juvenile suspect and expect to make additional arrests.